1. Field of the Invention
The present invention relates to an anisotropic conductive adhesive and an adhesive film using the same, and more particularly to an anisotropic conductive adhesive and an adhesive film using the same, which is characterized by including a crosslinked rubber resin in an insulating adhesive component.
2. Background of the Related Art
An anisotropic conductive adhesive is a circuit connecting material in which conductive particles are dispersed in an insulating adhesive component, which adheres mechanically circuits disposed in the opposite direction, and simultaneously interposes a conductive particle between the circuit electrodes to establish an electrical connection. As an insulating adhesive component, a thermoplastic resin and a thermosetting resin are usable, and the thermosetting resin is more preferably used in terms of connection reliability
In case of employing the thermosetting resin as an adhesive component, a connection is made by interposing an anisotropic conductive adhesive between connected-to-be-members, which is then heat-compressed. But this method needs a significantly long hardening reaction time at high temperature for obtaining improved connection reliability and sufficient adhesive strength. Typically, in case of epoxy resins, about 20 seconds at 140˜180° C. or about 10 seconds at 180˜210° C. is necessary for connection.
However, under these connection conditions, there has been a problem in that dropping-out of wirings, short circuit between adjacent electrodes, dislocation and the like occur. Recently in the field of precise electronic equipments, since the development of ultra-dense circuit is in progress, electrode width and electrode spacing are becoming very narrow, which makes these problems deepened. Also, a long-term connection lowers production efficiency, and for the efficiency improvement, 10 seconds or less of connection time is required.
Also, in order to overcome the above-mentioned problems, a connecting material using a radical polymerizable resin has been developed, in which a radical polymerization occurs by heating or light-hardening at low temperature, and then hardening is made by cross-link. But there is still a problem in that since contraction of the connecting material by polymerization occurs greatly, internal stress is accumulated in a connection part after hardening, which causes easy exfoliation of the connecting material. Also, in the case where an electrode spacing is narrow, the electrode spacing is reduced by the contraction of the connecting material, which causes a short circuit.